The present invention is directed at preventing sanitary system gases of RV's (recreational vehicles), trailer homes and the like from passing through the toilet's waste-passage and into the room where the toilet is located. It is also intended to adapt powered ventilation to such sanitary systems so as to prevent incurred problems due to this addition.
Typically there are two types of toilets in regards to their method of preventing sanitary system gases from passing through them and into the room where they are used. They are the water-trap-toilet and the mechanical-seal-toilet. The water-trap-toilet is generally used in permanent structures while the mechanical-seal-toilet is generally used in conveyances such as RV's. Water-trap-toilets provide a continuous positive seal between the toilet room and the sanitary system by trapping flushing water in its waste passage. Mechanical-seal-toilets provide a seal between the toilet room and the sanitary system with a valve located in its waste passage. When the valve is open, however, this seal is broken and communication between the room and sanitary system can occur.
Conventional sanitary systems typically used in recreational vehicles, trailer homes and the like consist of a holding tank located beneath the floor of the facility and a mechanical seal type toilet fixture. From time to time, to prevent over-filling, the holding tank contents are emptied through the tank drain piping and disposed of. Tank level is gauged by viewing it through the toilet waste passage. A vent line off the tank provides an inlet so that the contents are displaced by outside air during tank draining. Gases in the holding tank are prevented from entering the room within which the toilet is located by the toilet outlet valve located in the toilet's waste passage. However, when the valve is opened to empty the toilet's bowl, these objectionable gases can pass through this passage and into the facilities room.
It is proposed to add to such a system's vent piping a fan for the purpose of venting the toilet when its waste outlet valve is open. This would prevent tank gases from entering the facilities room during that time. The tank used in a conventional sanitary system is box shaped and located below the floor of the facilities enclosure to conserve space. The tank's toilet and vent openings are located on the tanks top side. This configuration presents a problem as the location of the vent opening is lower than the toilet outlet valve. This allows the tank to be filled to the top. When tanks are full or contents are in close proximity to the suction at the tank vent opening they can be sucked into the vent piping.
U.S. Pat. No. 3,571,822 to Shaw describes a mobile type sanitary system that ventilates an unconventional mechanical seal type toilet. Here ventilation occurs during use and during the flushing operation. Shaw does not describe his toilet's adaptability to a conventional system used in RV's, trailer homes and the like. He does suggest that the tank could be separate from the toilet but he does not show how it would be constructed or piped to a conventional system. The preferred embodiment shows the toilet and tank as one unit. In this configuration there is no problem as to the contents getting near enough to be sucked into the tank's vent opening as the tank vent opening is above the toilet outlet valve. This would be a problem with a conventional system as explained in the previous paragraph. A problem Shaw does not consider. It should be apparent to those skilled in the art that Shaw's invention would not be workable or dependable in a conventional sanitary system or system that allows toilet discharge or tank contents to get in close proximity to the systems vent take off. It is also unlikely the preferred embodiment of Shaw's invention would be used in a modern RV or house trailer as the utilization of space is a primary consideration in their design.
Shaw's invention would be complex and expensive to adapt to existing built or newly manufactured conventional type sanitary facilities. It would be expensive because adapting to an existing system would require the replacement of the conventional toilet with one capable of operating like Shaw's proposed system. Assuming his toilet were adapted to a conventional system and affixed to the standard connection off the holding tank it is likely that additional piping to the toilet would be necessary. This piping would be for the venting path to remove user generated gases during toilet use. The cost of the electrical controls is another factor. Its operation is complex. There are two switches to energize the venting fan. One switch is operated by the toilet's lid and the other by the flushing mechanism. The switch operated by the toilet's lid also energizes a solenoid valve. This valve is located in the venting path and allows ventilation of the bowl during use and would be a component of his toilet. Special considerations for the installation of the valve and switches would be necessary to meet electrical safety, operating and maintenance requirements. This venting path could also be a place where odors or insects are generated given the possibility of wastes or other material entering there.
In addition Shaw's toilet is unconventional in that it cannot have a toilet bowl cover due to its mode of operation. This is also true of the toilet seat which normally is left in the vertical position when not in use.
Ventilation of bowls of water-trap-toilets have been proposed in U.S. Pat. Nos. 1,401,091; 3,571,824; 3,192,539, and 3,938,201 and have found little or no use. Room ventilating fans have proved satisfactory for removing facility-user generated gases.
The Anderson U.S. Pat. No. 4,894,872 is not designed to prevent odors from passing through the toilet's waste passage. It is a waterless system that uses a toilet that provides no seal against odors. Ventilation through the toilet also is not a consideration as its waste receptacle has several inlet openings to the outside atmosphere. The toilet used in this system is a straight through open type as used in latrines. Preventing flow through the toilet in the direction of its enclosure is not indicated in the patent. Air flow through the toilet is not indicated in his patent. Ventilation of the waste receptacle is primary to reducing odors while increasing evaporation and decomposition of waste.
Harding's U.S. Pat. No. 4,922,557 is a holding tank ventilation system. It incorporates a solar powered fan that when operating is intended to reduce odors by introducing cooler air into the holding tank. This system uses a open toilet with no sealing means. Even if ventilation were continuous the inventor does not indicate ventilation as a means to prevent tank odors from passing through the toilet.
Bussard's U.S. Pat. No. 3,873,445 is not directed at ventilation of a mechanical seal type toilet as he utilizes a water-trap type toilet in his invention. If a mechanical seal toilet were used in his facility, proper ventilation would not be possible as there is no negative pressure in the waste receptacle.
Ellis' U.S. Pat. No. 3,570,016 shows a portable toilet system that uses an open toilet as found in latrines. Powered ventilation of the toilet is not indicated in the patent. A room ventilation fan is used only for the ventilation of the toilet's enclosure. It is possible that if the sealing lid of the toilet were open that this fan could draw the gases of the system into the toilet's enclosure. In any event, communication between the enclosure and system is possible when the toilet's sealing lid is open.